| 1 | Nano-phase transformation of composite precipitates in multicomponent Al-Mg-Si(-Sc)alloys显示文摘Sc-addition can significantly enhance the performance of the micro-alloyed Al-Mg-Si-Sc alloys.However,the mechanisms by which the Sc element modifies the microstructure of the alloys are still unknown in many cases.Here,using atomic-scale transmission electron microscopy and atomic-resolution spectroscopy,we have revealed the microstructural differences between two age-hardened Al-0.5Mg-0.4Si(wt.%)alloys with and without Sc-addition.The first significant effect of Sc-addition on the precipitation microstructure of the Al-Mg-Si-Sc alloy is that Sc-atoms may distribute at theβ'-precipitate/Al-matrix interface and therefore accelerate aging kinetics at the initial stage of hardening.The second significant effect of Sc-addition is that in the transition from theβ'-hardened peak-age stage to theβ′-hardened late stage,Sc-atoms can greatly improve the stability of transitionalβ'/B'/β′composite precipitates by entering the B'-substructures and/or locating at the precipitate/Al interfaces.As such Sc-atoms effectively suppressβ'toβ'transformation and cross-sectional coarsening of bothβ'and composite precipitates,leading to much finer precipitate needles with smaller diameter but much larger length,as compared with those precipitate needles formed in the alloy without Sc-addition.Hence,the alloy with Sc-addition exhibits a much better thermal stability than that without Sc. | S.B.Wang C.F.Pan B.Wei X.Zheng Y.X.Lai J.H.Chen | 2022 | Journal of Materials Science & Technology2022，，15： | 1 |
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